No matter how good the fish tank filter you buy it is important to check that you are using the best media for your actual aquarium. The type of filter media that you have determines if the water remains safe for your fish and plants.
In simple terms the filter media will clean and purify the water. The amount of work it has to do depends on what you have in the tank that will contaminate the water. The main objective of the fish tank filter is to clean the aquarium water in different ways i.e. chemically, biologically and mechanically.
Mechanical media removes the larger particles in the water therefore eliminating the biggest physical problem. This helps to prevent clogging the fish tank filter. Mechanical media includes pads, sponges, floss and even wood as well as a range of plastic shaped pieces that are made for each filter. Normally this type of filtration is not enough as it is not effective in removing nitrate and ammonia which can build-up in the water and is very dangerous for fish. If this is the first filter media that you place in the filter line, it would help in capturing the debris before it even reaches the other layers of the filters. If you are relying on your mechanical filter to aerate, make sure you have the right size filter for the tank. If you dont, you will not have enough oxygen in your tank, you will not decompose the bad bacteria. This can lead to a build-up of ammonia and nitrites.
Dual purpose media is a great method of combining mechanical and biological filtration. Many aquarists prefer to filter the water in a dual way using a biological as well as in a mechanical media. The bonded pads and the sponges can be used both as a mechanical as well as a biological media for filtering the water. By combining different layers which have varied degree of coarseness the media can remove the bulky waste and also provide biological cleaning through the bacteria on the media. This media, however, requires regular cleaning of the layers from time to time.
Biological filtration for your fish tank is the most important filtration. It is critical to get this right. Good bacteria breaks down ammonia and nitrites in your aquarium. Oxygen is great for encouraging good bacteria to thrive in the tank too. There are a few ways to add oxygen to the water at an increased rate so our good bacteria can grow to take care of the ammonia and nitrites. Getting a surface agitator or bubbler in your tank is so easy, inexpensive, and very effective. It puts oxygen in the water at a faster rate and even helps stir your tank so you are filtrating properly.
Chemical media are also used by aquarists when they wish to remove the toxins and other chemicals from the water and wish to alter the chemical properties of the medium. Usually, you are going to be using activated charcoal for this. The activated charcoal is going to get rid of all of the particles whether they be waste, food, or pieces of plant that have decomposed in your tank. If you are having trouble with creating the optimal environment for a biological filter and mechanical filter, the chemical filter is a natural next step. There is a lot to consider with water chemistry and this is whole new topic on its own. It is very important to read more about water chemistry before starting to add chemicals to your tank.